离子液体中Co掺杂介孔TiO2可见光催化剂的制备及性能研究

以离子液体([C₄MIM]BF₄)为模板剂, 采用溶胶-凝胶法制备了介孔TiO₂和Co掺杂的介孔TiO₂光催化剂。研究了Co掺杂对样品的比表面积、晶相、元素价态、吸光特性及可见光活性的影响。结果表明: 所制备的Co/TiO₂光催化剂为介孔结构的具有较大比表面积的锐钛矿相纳米颗粒; XPS分析表明: Co以Co²⁺取代Ti⁴⁺进入TiO₂晶格形成杂质能级, 降低了TiO₂带隙能, 有效拓展了TiO₂的光响应范围。以亚甲基蓝水溶液为降解对象, 在可见光 (λ>420 nm)下考察制备样品的光催化活性, 结果表明: Co掺杂的TiO₂具有可见光活性, 且0.3%Co/TiO₂的活性最高。

Preparation and Properties of Co-doped TiO2 with Assistance of Ionic Liquid

Co-doped mesoporous TiO₂ photocatalysts were prepared by an ionic liquid 1-butyl-3-methylimida-zolium tetrafluoroborate ([C₄MIM]BF₄) modified Sol-Gel method. The effects of Co doping on the surface area, crystalline phase, chemical binding states and compositions, and absorbance of the Co-doped mesoporous TiO₂ photocatalysts were studied by N₂ adsorption-desorption measurements (BET), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance absorption spectra (UV-Vis DRS). BET analysis showed that Co/TiO₂ photocatalyst was mesoporous structure with large surface area. XRD patterns indicated that the Co-doped mesoporous TiO₂ photocatalysts was anatase structure. XPS spectra indicated that the Co²⁺ replaced Ti⁴⁺ and entered into TiO₂ lattice, which reduced the band gap of TiO₂ and thereby extending the light response range to the visible region (UV-Vis spectra). Photocatalytic activity of the Co/TiO₂ mesoporous photocatalysts was evaluated by photodegradation of methylene blue (MB) under visible light (λ>420 nm). Co-doped TiO₂ exhibited obvious visible light activity for MB photodegradation, and 0.3%Co/TiO₂ exhibited the highest photocatalytic activity.